What was the Yalta conference?

When it became clear that Germany was going to lose the war, the Allied leaders met at Yalta to decide on the shape of Europe in the postwar years.
Churchill, Stalin and Roosevelt decided to divide Germany into four zones, to be controlled by Russia, the United States, Britain and France. These zones were intended to keep Germany weak and to prevent any further hostilities.

At later conferences, agreements were made to give some captured German territory to Poland and Russia.